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The parent plants used in these tests were not 

 Practical specially selected; and better results would un- 



suggestions doubtedly have been secured if, for one or two 

 for seed generations previously, high-yielding mother 

 growing. plants had been chosen. This could easily 

 have been done, and the strain kept pure, 

 since tomatoes are readily self-fertilized. These high-yielding 

 strains should be continued and new crosses made as new seed is 

 needed. The crossing need not be done every year, since tomato 

 seed retains its vitality for at least three years, so that enough 

 crossed seed could be secured in one season to grow the crop for 

 three years to follow. But the tomato grower who does not regu- 

 larly raise his own seed must buy the crossed seed each year un- 

 less he wishes to find his second-season crop running down in 

 yield. The improvement in yield is not inherent in the strain; 

 it is merely the result of the crossing. 



Too violent crossing must not be attempted else sterility will 

 result, as in the well known case of the mule. In crossing the 

 tomato and Jerusalem cherry at this Station total sterility 

 resulted. 



The best results can probably be secured by keeping within the 

 species and crossing the distinct varieties and the distinct strains ; 

 and in selecting these, regard must be paid to the inheritance of 

 such qualities as smoothness, color, shape, size and earliness. 

 To obtain smooth fruits only varieties producing smooth, even- 

 surfaced fruits should be used, since roughness appears in the 

 first generation. If dark red tomatoes are desired, one of the 

 parents at least must be dark red ; but the other may be red, pink 

 or yellow, since the red is a stronger character than the pink or 

 yellow and will hide them in the first generation. If pink is de- 

 sired the red must be avoided and two pink varieties or a pink 

 and a yellow used; while to get yellow fruits both parents must 

 be yellow. 



Size appears to be inherited in a blended condition, as it is 

 probably not a unit character ; therefore to obtain tomatoes of 

 large size, both parents must produce large fruits, to produce small 

 ones both parents must be small-fruited ; while to produce medium- 

 sized fruits, either medium-fruited parents must be crossed or 

 small-fruited and large-fruited types. The same condition pre- 

 vails with regard to general shape as with size, — an intermediate 

 inheritance ; and earliness probably follows the same rule. 



